Ion implantation is a process of introducing dopants or impurities into a substrate via bombardment. Ion implantation systems may comprise an ion source and a series of beam-line components. The ion source may comprise a chamber where ions are generated. The beam-line components, may include, for example, a mass analyzer, a collimator, and various components to accelerate or decelerate the ion beam. Much like a series of optical lenses for manipulating a light beam, the beam-line components can filter, focus, and manipulate an ion beam having particular species, shape, energy, and/or other qualities. The ion beam passes through the beam-line components and may be directed toward a substrate mounted on a platen or clamp.
One type of ion implanter suitable for generating ion beams of medium energy and high energy uses a linear accelerator, or LINAC, where a series of electrodes arranged as tubes around the beam accelerate the ion beam to increasingly higher energy along the succession of tubes. The various electrodes may be arranged in a series of stages where a given electrode in a given stage receives an AC voltage signal to accelerate the ion beam.
LINACs employ initial stages that bunch an ion beam as the beam is conducted through the beamline. An initial stage of a LINAC may be referred to as a buncher, where a continuous ion beam is received by the buncher and is output as a bunched ion beam in packets. Depending upon the frequency of the AC voltage signal and the amplitude, the acceptance or phase capture of an ion beam conducted through a known “double-gap” buncher using one powered electrode may be on the order of 30-35%, meaning that 65% of more of beam current is lost while being conducted into the acceleration stages of the linear accelerator.
With respect to these and other considerations, the present disclosure is provided.